Integration of SNMP and CMIP

ABSTRACT

Many systems deployed by telecommunications operators will, in the future, include both Simple Network Management Protocol (SNMP) and Common Management Information Protocol (CMIP) management mechanisms. The disclosed system solution is a mechanism which enables CMIP to be implemented directly on top of SNMP. By using this mechanism, security and administrative mechanisms that are included in SNMP version 2, or SNMP version 1.5, can be reused for CMIP. This enables telecommunications operators to actively fight the network complexity inflation that is currently placing a heavy burden on telecommunications networks.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to protocol architectures, for use innetwork management of telecommunications systems, methods of managingtelecommunications networks and telecommunications network managementsystems.

2. Discussion of the Background

For the avoidance of doubt, it should be noted that network managementsystems, in telecommunications, refer to the equipment, software, andmethods used to control the technical operation of a telecommunicationsnetwork. Inventions relating to network management systems are based ontelecommunications technology and invariable have a direct and realeffect on the operation of telecommunications equipment such astelephone exchanges, ATM systems, intelligent networks, and the like.

Most computer systems, including those that control network elementsimplementing SDH (Synchronous Digital Highway), ATM (AsynchronousTransfer Mode), SS7 (ITU-T Signalling No. 7) and others, will, in thefuture, be equipped with management facilities conforming to SNMP (theInternet Simple Network Management Protocol). This is also true for mostCPE (Customer Premises Equipment). Similarly, many of the aforementionedcomputer systems will be equipped with ISO-oriented managementprotocols, in particular CMIP, (ISO/ITU Common Management InformationProtocol). It is likely that CMIP and SNMP will coexist for a longperiod of time. It is also likely that SNMP will, in many cases, be usedto implement point-to-point, low-level, element management. CMIP will bedeployed as an instrument to coordinate those SNMP-based managementsystems on a network, service and business, wide level.

SUMMARY OF THE INVENTION

The present invention is intended to facilitate a sharing ofcommunication resources between SNMP and CMIP. Many systems deployed bytelecommunications operators will, in the future, consist of both SNMPand CMIP management mechanisms. An example of such a system is the TeliaCity Service's ATM network. The systems solution, of the presentinvention, proposes a mechanism which will enable CMIP to be implementeddirectly on top of SNMP. By using this mechanism, security andadministrative mechanisms that are included in SNMPv2, or SNMPv1.5, canbe reused for CMIP. This will enable telecommunications operators toactively fight the network complexity inflation that is currentlyplacing a heavy burden on telecommunications networks.

An octet-oriented approach has been defined by Marshall Rose (InternetRFC 1185) for using data generated by BER and then feeding this datadirectly into TCP. However, this method is purely a data transporttechnique and does not cater for utilization of administrative andsecurity frameworks and resources already in place for SNMP.

According to a first aspect of the present invention, there is provideda telecommunications system, including a network management centre andat least one network element, in which network management data istransmitted, at least partially, over a link(s) employing CMIP and SNMP,characterised in that SNMP based management protocols are reused as atransport mechanism for CMIP PDUs.

Said SNMP may have a security and administrative framework that isreused for said CMIP.

After serialisation of CMIP PDUs into octet strings, the octet stringsmay be encapsulated into SNMP PDUs for transmission.

The octet strings may include a MIB tree reference.

Said telecommunications management centre may include a serializeradapted to transform CMISE/ROSE ASN.1 data structures to a string ofoctets.

Said telecommunications system may include at least one networkmanagement system, said network management centre may transmit saidnetwork management data to said at least one network element via said atleast one network management system, and said network management datamay be transmitted between said network management centre and saidnetwork management system using either CMIP, or SNMP.

Said telecommunications system may include a plurality of networkmanagement systems.

Said telecommunications system may include a plurality of networkelements, and said network elements may include SDH, ATM, SS7.

Said telecommunications system may include a first and second CMISE,said first CMISE may be adapted to establish an association with saidsecond CMISE, and said association may specify a presentation context.

Said presentation context may be ROSE.

Once said association is established, CMIP may work on top of ROSE,which may work on top of a serializer that transforms ASN.1 datastructures from CMISE/ROSE to a string octet according to BER.

Strings of octets produced by said serializer may be conveyed to a localSNMP interface which can be either a manager, or an agent.

Said octet strings may include a MIB-tree reference pertaining to saidoctet strings' origin, said MIB-tree reference may function as an entryto a set of variables and tables acting as a repository for CMISE/ROSEgenerated octet strings.

When an initiating CMISE side of a manager/agent border exchange servicehas identified a MIB-tree reference, pertaining to a particularassociation and invocation, it may cause a generated octet string to bewritten into a MIB variable/table entry on the other side of amanager/agent border exchange service.

Said network element may be an ATM switch.

According to a second aspect of the present invention, there isprovided,a protocol architecture, for transmission of network managementdata using both CMIP and SNMP, characterised in that SNMP basedmanagement protocols are reused as a transport mechanism for CMIP.

The SNMP's security and administrative framework may be reused for CMIP.

CMIP PDUs may be serialised, into octet strings, and encapsulated intoSNMP PDUs.

The octet strings may include a MIB tree reference.

The process of serialisation may transform CMISE/ROSE ASN.1 datastructures into a string of octets.

A first CMISE may be adapted to establish an association with a secondCMISE, and said association may specify a presentation context.

Said presentation context may be ROSE.

CMIP may work on top of ROSE, which may work on top of the process ofserialization that transforms ASN.1 data structures from CMISE/ROSE to astring octet, according to BER.

Strings of octets produced by said process of serialization may beconveyed to a local SNMP interface which can be either a manager, or anagent.

Said octet strings may include a MIB-tree reference pertaining to saidoctet strings' origin, and said MIB-tree reference may function as anentry to set of variables and tables acting as a repository forCMISE/ROSE generated octet strings.

An MIB may be linked to a layer 2 service provider via a first protocolstack which may include CMISE/CMIP and ROSE.

Said first protocol stack may include SMASE.

An MIB may be linked to a layer 2 service provider via a second protocolstack which includes SNMP, UDP and IP.

Said first protocol stack may include said second protocol stack.

According to a third aspect of the present invention, there is provideda method of managing a telecommunications system, saidtelecommunications system, including a network management centre and atleast one network element, in which network management data istransmitted, at least partially, over a link(s) employing CMIP and SNMP,said method characterised by reusing SNMP based management protocols asa transport mechanism for CMIP PDUs.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example,with reference to the accompanying drawings, in which:

FIG. 1 illustrates a known architecture for network management of atelecommunications network.

FIG. 2 illustrates a known protocol architecture for use in a networkmanagement system.

FIG. 3 illustrates a protocol architecture according to the presentinvention.

FIG. 4 illustrates the use of a network management system to set up anATM connection between two subscribers.

FIG. 5 illustrates a further aspect of the protocol architecture shownin FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To facilitate an understanding of the present invention, a glossary ofthe abbreviations used in this patent specification are set out below:

ACSE: Association Control Service Element

AP: Application Process

ASN.1: Abstract Syntax Notation No. 1

ATM: Asynchronous Transfer Mode

BER: Basic Encoding Rule

CMIP: Common Management Information Protocol (ISO/ITU)

CMISE: CMIP Service Element

CPE: Customer Premises Equipment

IP: Internet Protocol

ISO: International Standards Organisation

ITU: International Telecommunications Union

MIB: Management Information Base

NMC: Network Management Centre

NMS: Network Management System

OID: Object ID

OSI: Open Systems Interconnect

PDU: Protocol Data Unit

ROSE: Remote Operations Service Element

SDH: Synchronous Digital Highway

SMASE: Service Management and Administration Entity?

SNMP: Simple Network Management Protocol (Internet)

SS7: ITU Signalling System No. 7

TCP: Transmission Control Protocol

UDP: User Datagram Protocol (Internet)

VP: Virtual Path

vpCTPBid: VP Connection Termination Point Bidirectional

VPI: Virtual Path Identifier

The embodiment of the present invention described here, relates to theTelia City Services ATM network.

CMIP will be introduced into telecommunications networks to coordinatelower level NMSs and will start to penetrate the management network fromabove. Referring now to FIG. 1, there is illustrated a typicaltelecommunications management network, which can conceptually be splitinto an operator domain and a user domain. The network managementcentre, NMC, communicates with network management systems, NMS, by CMIP,or SNMP. In many cases both management protocols, CMIP and SNMP, willcoexist. The NMSs will communicate with each other and ATM switches andcross-connects using SNMP. Again, communications within the ATM network,between ATM switches, cross-connects and customers will use SNMP.

Most computer systems, including those that control network elementsimplementing SDH, ATM, SS7 and others, will in the future be equippedwith management facilities conforming to SNMP. This is also true formost CPE. Similarly, many of the aforementioned computer systems will beequipped with ISO-oriented management protocols, in particular CMIP. Itis likely that CMIP and SNMP will coexist for a long period of time. Itis also likely that SNMP will, in many cases, be used to implementpoint-to-point low-level element management. CMIP will be deployed as aninstrument to coordinate those SNMP-based management systems on anetwork, service and business, wide level.

Thus, it will be necessary for SNMP and CMIP to coexist in an efficientmanner which does not lead to network complexity inflation.

Instead of requiring a totally separate protocol stack for CMIP, asopposed to the infrastructure already available through SNMP, thesystems solution of the present invention provides a method of reusingthe ubiquitous SNMP-based management protocols as a transport mechanismfor CMIP, see FIGS. 2 and 3, which contrast the traditional protocolarchitecture used in network management systems with the protocolarchitecture of the present invention.

Referring first to FIG. 2, there is illustrated a traditional protocolarchitecture used in network management systems. On the one hand, a MIBlinks through to a SMASE and thence to an ACSE, and, via a CMISE/CMIP toa ROSE. These protocols are, in turn, linked to the presentation andsession layers, and thence via the transport layer, using the followingprotocols, RFC1006, TCP and IP, to layer 2 service providers. On theother hand, a MIB is linked directly via a SNMP, to the transport layerwhich uses the following protocols, UDP and IP, and thence to the layer2 service providers. This illustrates how network complexity inflationcan occur.

By way of contrast, the protocol architecture of the present inventionis illustrated in FIG. 3. In this case, the administrative and securityparts on one of the two MIBs is reused in the other MIB. One MIB islinked to an ACSE and, via a CMISE/CMIP, to a ROSE, in a similar mannerto that described with respect to FIG. 2. The ROSE and ACSE are thenlinked to a serializer and thence, via the system solution of thepresent invention, to a SNMP. The second MIB can be linked directly to aSNMP, or via the system solution to the serializer. Both MIBs are thenlinked, via the transport layer, using a UDP and IP, to a layer 2service provider such as ATM.

There are two main underlying protocols of pertinence to CMIP: ACSE andROSE. The user, e.g. the manager, of the CMIP Service Element (CMISE),typically establishes an association with another CMISE user, e.g. anagent. The association specifies a presentation context that includesROSE and, in some cases, also other application service elements.

Referring now to FIG. 4, there is shown the connection between a Teliaoperator, 1, and an ATM switch, 4. The Telia operator, 1, is linked viathe Internet, 2, to the NMC, 3, for Göteborg. The NMC for Göteborg islinked to the ATM switch for Göteborg. A first port, 7, of the ATMswitch 4, is linked, 9, to a customer, 5, located in Stockholm, by a VPhaving VPI “42”. A second port, 8, of the ATM switch 4, is linked, 10,to a customer, 6, located in Malmö, by a VP having VPI “43”. A stream ofATM cells are routed between customer 6 and customer 5, via ATM switch4. System control is effected, by the operator, through the followingsteps:

1. The Telia operator establishes an association with the NMC, 3,controlling ATM switch, 4, and specifies that CMISE and ROSE will beused as presentation contexts, by sending the following “AASSOCIATE.request”:

Application-context-name=“CMIP+ROSE”

Calling-AP-title=“Telia-OSI-Manager-i-Farsta”

Called-AP-title=“Telia-QSI-Agent-i-Göteborg”.

2. The NMC, 3, acknowledges the request by sending the following“A_ASSOCIATE.response”:

(Accept).

There is now a management association between the manager and the agentthat controls the switch/cross-connect.

3. The operator now issues an M-action command to establish a connectionbetween customers 5 and 6 who may be on two ends of a corporate network.The M-action command takes the form of an “M-ACTION.request” in thefollowing form:

BaseObjectClass=atmFabric

ActionType=connect

ActionInformation=vpcCTPBid142, vpCTPBid243

The “M-ACTION.request” is mapped onto ROSE and then serialized beforebeing sent over the OSI presentation/session/transport layers as“RO-INVOKE.request (M-ACTION)”.

4. The ROSE invocation is received by the agent and passed to a CMIP as“RO-INVOKE (M-ACTION)”.

5. The CMIP issues an “M-ACTION.indication” in the form:

BaseObjectClass=atmFabric

ActionType=connect

ActionInformation=vpcCTPBid142, vpCTPBid243

The agent now issues an order to the switch to cross-connect ports so asto establish a path between customers 5 and 6.

Over ROSE, the CMISEs, on both sides of the manager/agent border,exchange service requests and responses, e.g. to create a cross-connectobject on an ATM switch, or to collect accounting information from aparticular connection to which a customer has subscribed. Theimplementation of ACSE over SNMP is the subject of another systemssolution and is not covered by this patent application. For the purposesof the present invention, it may be assumed that the implementation ofACSE over SNMP always exists, or that it is established out-of-band.Once an association has been established, CMIP works on top of ROSE,which in turn works on top of a serializer that transforms ASN.1 datastructures from CMISE/ROSE to a string of octets according to BER.

With the systems solution of the present invention, once a string ofoctets has been produced by the serializer, the string is conveyed tothe local SNMP service interface. This can be an agent, or managerinterface. The means by which SNMP message exchanges, between agent andmanager, is achieved is immaterial to this patent application since theycan be of any type, e.g. GET, SET, TRAP, INFORM etc. The octet stringcomes with a MIB-tree reference, i.e. OID (Object ID) pertaining to theentity that produced it. For example, if the origin is CMISE/ROSE, thenan OID could be “enterprise.telia.management.cmip over snmp”. This OIDis an entry to a set of variables and tables that play the role ofrepository of CMISE/ROSE generated octet strings.

Referring now to FIG. 5, there is illustrated, in diagrammatic form, thesystem solution of the present invention in which SNMP administrativeand security frameworks are reused for CMIP. After serialization of aCMIP PDU, in the traditional manner, the octet string is passed to thelower parts of the presentation layer and thence to the session layerand other ISO layers. With the system solution, according to the presentinvention, the octet string is encapsulated into an SNMP PDU (version1.5, or version 2) and sent to the agent.

A, for example, RO_INVOKE is put into an ASN.1 structure, see FIG. 5,and passed to the serializer/deserializer. The resultant octet string isthen encapsulated in an SNMP PDU. The administrative and securityframework, 20, maps the Application Process Title, e.g.“Telia-OSI-Manager-i-Farsta” to SNMP context and IP address. The SNMPPDU is then passed from the manager to the agent in the form of, forexample GET, SET, TRAP, INFORM etc..

When the initiating CMISE side has identified the OID pertaining to theassociation and to a particular invocation, it writes the generatedoctet string into the MIB variable/table entry on the other side. Thisentry will function as a buffer for the octet string betweenserializer/deserializer and SNMP. Note that the current status of SNMPv2is unstable, in particular with respect to the proposed security andadministrative models as they stand today. However, this proposal basesits SNMP leg on SMI II (Specification of Management Information, theInternet slimmed-down version of ASN. 1) which can be considered verystable.

Typically, there could be one single table into which ROSE/CMISE octetstrings are written. However, the present invention is not limited tothe manner in which octet strings are written, but rather extends to allways in which octet strings relating to ASN.1 serializers/deserializersare represented in the SNMP MIB. The table can be indexed through anassoc index (pertaining to the association) and an invocation indexrelevant to a particular transaction over the association. The elementsof the table can also be stored once the association is deleted, e.g. tokeep a record of events that occurred between manager and agent over theassociation. No matter what SNMPv2/v1.5 security mechanism is used, e.g.party-based, or user-based, there will be a possibility to relate theMIB-tree of an agent to access rights of a manager. Note, however, thatthe systems solution requires an integrity mechanism to be present inSNMP, in particular if UDP is used, since integrity checks will alsofunction as protection against errors in the PDUs, see FIGS. 2 and 3.

Initially, most network elements in Telia's ATM/SDH network will bemanaged through SNMP. This is the situation at the present time. CMIPwill be introduced as a vehicle for management information exchangebetween Telia and other operators. However, with the systems solution ofthe present invention, the initial costs of taking the step from SNMP toCMIP will be greatly reduced. Thus, the present invention, will enable atelecommunications operator to focus on the real benefits from OSImanagement, i.e. the systems management functions such as scheduling,accounting, log, testing etc. The same infrastructure that is now inplace for SNMP will be used as an administrative and security tool toimplement CMISE message exchanges.

What is claimed is:
 1. A telecommunications system, comprising: anetwork management center; a plurality of network elements connected tosaid network management center, said network elements includingSynchronous Digital Highway (SDH), Asynchronous Transfer Mode (ATM), andInternational Telecommunications Union (ITU) Signaling System NO. 7(SS7), wherein for at least one of said plurality of network elements,network management data is transmitted, at least partially, over a linkemploying Common Management Information Protocol (CMIP) and SimpleNetwork Management Protocol (SNMP); and a first and a second CommonManagement Information Service Element (CMISE) connected to said networkmanagement center, said first CMISE is adapted to establish anassociation with said second CMISE, said association specifies apresentation context, the SNMP based management protocols are reused asa transport mechanism for CMIP Protocol Data Units (PDUs); the CMIP PDUsare serialized into octet strings, and the octet strings areencapsulated into SNMP PDUs for transmission; said presentation contextis Remote Operation Service Element (ROSE); and wherein with saidassociation established, CMIP works on top of ROSE, which works on topof the process of serialization that transforms data structures fromCMISE/ROSE into the octet strings.
 2. A telecommunications system, asclaimed in claim 1, wherein said octet strings produced by saidserializer are conveyed to a local SNMP interface which can be either amanager or an agent.
 3. A telecommunications system, as claimed in claim2, wherein said octet strings include a MIB-tree reference pertaining tosaid octet strings' origin, and said MIB-tree reference functions as anentry to a set of variables and tables acting as a repository forCMISE/ROSE generated octet strings.
 4. A telecommunications system, asclaimed in claim 3, wherein when an initiating CMISE side of amanager/agent border exchange service has identified a MIB-treereference, pertaining to a particular association and invocation, itcauses a generated octet string to be written into a MIB variable/tableentry on the other side of a manager/agent border exchange service.
 5. Aprotocol network architecture, for transmission of network managementdata, comprising: a Common Management Information Protocol (CMIP); and aSimple Network Management Protocol (SNMP), wherein the SNMP basedmanagement protocols are reused as a transport mechanism for CMIPProtocol Data Units (PDUs), the CMIP PDUs are serialized into octetstrings, and the octet strings are encapsulated into SNMP PDUs; theoctet strings include a Management Information Base (MIB)-treereference; the process of serialization transforms Common ManagementInformation Service Element/Remote Operation Service Element AbstractSystem Notation One (CMISE/ROSE ASN.1) data structures into a string ofoctets; a first CMISE is adapted to establish an association with asecond CMISE, said association specifies a presentation context; saidpresentation context is ROSE; and the CMIP works on top of ROSE, whichworks on top of the process of serialization that transforms the datastructures from CMISE/ROSE to the octet strings.
 6. A protocol networkarchitecture, as claimed in claim 5, wherein said octet strings producedby said serializer are conveyed to a local SNMP interface which can beeither a manager or an agent.
 7. A protocol network architecture, asclaimed in claim 6, wherein said octet strings include a MIB-treereference pertaining to said octet strings' origin, and said MIB-treereference functions as an entry to a set of variables and tables actingas a repository for CMISE/ROSE generated octet strings.
 8. A method ofmanaging a telecommunications system, said telecommunications systemincluding a first and a second Common Management Information ServiceElement (CMISE), a network management center, and at least one networkelement, wherein network management data is transmitted, at leastpartially, over a link employing Common Management Information Protocol(CMIP) and Simple Network management Protocol (SNMP), comprising thesteps of: reusing SNMP based management protocols as a transportmechanism for CMIP Protocol Data Units (PDUs); serializing CMIP PDUsinto octet strings; encapsulating the octet strings into SNMP PDUs fortransmission; establishing an association with said second CMISE by saidfirst CMISE; and specifying a presentation context by said association;specifying said presentation context as Remote Operation Service Element(ROSE); enabling the CMIP working on top of the ROSE, once saidassociation is established; and enabling the ROSE working on top of aserialization process that transforms data structures from CMISE/ROSEinto the octet strings.
 9. A method, as claimed in claim 8, furthercomprising the step of conveying strings of octets produced by saidserialization process to a local SNMP interface which can be either amanager or an agent.
 10. A method, as claimed in claim 9, further thesteps of: including a MIB-tree reference pertaining to said octetstrings' origin in said octet strings; enabling said MIB-tree referencefunctioning as an entry to a set of variables and tables; and enablingsaid MIB-tree reference acting as a repository for CMISE/ROSE generatedoctet strings.
 11. A method, as claimed in claim 10, further comprisingthe steps of: initiating a CMISE side of a manager/agent border exchangeservice; identifying a MIB-tree reference pertaining to a particularassociation and invocation; and causing a generated octet string to bewritten into a MIB variable/table entry on the other side of amanager/agent border exchange service.